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non blocking connect

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# 1  
Old 09-05-2010
non blocking connect
OS : solaris 10 X86

I created stream socket, tries to connect to port 7 on the remote machine.
After doing the non blocking connect call I did select with time out value is 3 secs. I am always getting timed out though I am writing prior to select.

code:

Code:
x=fcntl(S,F_GETFL,0);
fcntl(s,F_SETFL,x | O_NONBLOCK);
rc=connect(s, (struct sockaddr *)&sin, sizeof(sin));
if( rc == 0)
  write(s,"service",7);
else
{
   if( errno == EINPROGRESS)
   {
        write(s,"service",7);
     FD_ZERO(&writeFDs);
     FD_SET(s, &writeFDs);
     rc=select(maxFDs, &writeFDs, (fd_set *) NULL, (fd_set *)NULL, 
                                                                (struct timeval *)(&timeout));
     if( rc ==0 || rc == -1)
       printf(" Timed out -- Not connected even after 3 secs wait");
    else
      printf(" connected and written");
}

My doubt is write on non blocking socket will happen or write fails and select will timeout. What do I have to do to connection successful

Moderator's Comments:
Mod Comment After more than 40 posts you should know how and when to apply code tags


---------- Post updated 09-05-10 at 01:11 PM ---------- Previous update was 09-04-10 at 11:56 PM ----------

I found wrong in my code. I should move my write to the else part and I should set read flags as NULL and write flags as my socket.

---------- Post updated at 01:15 PM ---------- Previous update was at 01:11 PM ----------

my code should be

Code:
if( errno == EINPROGRESS)
{        
     FD_ZERO(&writeFDs);
     FD_SET(s, &writeFDs);
     rc=select(maxFDs, (fd_set *) NULL, &writeFDs,  (fd_set *)NULL, 
                                                                (struct timeval *)(&timeout));
     if( rc ==0 || rc == -1)
       printf(" Timed out -- Not connected even after 3 secs wait");
    else
       write(s,"service",7);

Last edited by pludi; 09-05-2010 at 06:51 AM..
# 2  
Old 09-08-2010
I am connecting to port 7(echo service) in the remote machine.
suppose port 7 is not running in the remote machine I do not want to wait in connect call for long time.. so I am using non blocking connect with timeout of 3 seconds. But I am always getting the return code 1 from select call though the echo service is not running incase of write falgs set.

Code:
x=fcntl(S,F_GETFL,0);
fcntl(s,F_SETFL,x | O_NONBLOCK);
rc=connect(s, (struct sockaddr *)&sin, sizeof(sin));
if( errno == EINPROGRESS)
{        
     FD_ZERO(&writeFDs);
     FD_SET(s, &writeFDs);
     rc=select(maxFDs, (fd_set *) NULL, &writeFDs,  (fd_set *)NULL, 
                                                                (struct timeval *)(&timeout));
     if( rc ==0 || rc == -1)
       printf(" Timed out -- Not connected even after 3 secs wait");
    else
    {
	if(FD_ISSET(s,&writeFDs))
       	write(s,"service",7);
    }
}

In the above FD_ISSET is returning true and when it tries to write it retrun EPIPE, because of not connected. How we decide that service is ready for writing?
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